systems and methods for treating liquid effluent, the effluent including contaminants capable of biodegradation, using biodegradation beds. While the effluent holding tank is housed within a containment facility in the event of holding tank rupture or leakage, the biodegradation beds and an excess effluent sump are housed adjacent but outside the containment facility. In some aspects, the biodegradation beds are covered with generally transparent covers to allow sunlight to heat the bed contents and effluent for degradation and evaporation purposes while avoiding introduction of unwanted ambient precipitation.
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1. A system for treating liquid effluent, the effluent comprising contaminants capable of biodegradation, the system comprising:
a tank intake line for feeding the effluent to a holding tank;
a containment facility for housing the holding tank;
a tank outlet line for removing the effluent from the holding tank;
a pump on the tank outlet line for pumping the effluent out of the holding tank;
a line exit at a terminal end of the tank outlet line, the line exit positioned outside the containment facility;
at least one biodegradation bed situated beneath the line exit and outside and beneath the containment facility, the at least one biodegradation bed configured for receipt of the effluent from the line exit, the at least one biodegradation bed comprising organic material and microorganisms, the organic material and microorganisms suitable for degrading the contaminants in the effluent as the effluent passes downwardly through the at least one biodegradation bed by gravity, thereby producing a treated stream;
a bed outlet line for removing the treated stream from the at least one biodegradation bed;
an overflow line, connected to the top of the biodegradation bed, for removing excess amounts of the effluent from the at least one biodegradation bed and directing the excess amounts to a sump tank positioned outside the containment facility; and
an excess amounts reintroduction line for directing at least a portion of the excess amounts from the sump tank to the holding tank,
and wherein the effluent comprises rinsate derived from washing agricultural implements.
2. The system of
3. The system of
4. The system of
at least one moisture sensor in the at least one biodegradation bed, the at least one moisture sensor configured to detect the moisture level in the at least one biodegradation bed and output a bed moisture level signal representing the bed moisture level;
a moisture control station for receiving the bed moisture level signal and comparing the bed moisture level against an operating moisture level; and
the moisture control station for outputting control information to the pump;
such that if the bed moisture level is greater than the operating moisture level, the pump is directed by the moisture control station to cease pumping the effluent out of the holding tank; and
such that if the bed moisture level is less than the operating moisture level, the moisture control station allows the pump to continue pumping the effluent out of the holding tank.
5. The system of
a manifold for dividing the line exit into a plurality of line exits, each of the plurality of line exits for directing the effluent to one of the biodegradation beds.
6. The system of
7. The system of
8. The system of
9. The system of
10. The system of
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This application is a National Stage entry of International Application No. PCT/EP2019/060693, filed 26 Apr. 2019, which claims priority to Canadian Patent Application No. 3003220, filed 30 Apr. 2018.
The present invention relates to treatment of contaminated liquid effluent such as phytosanitary effluent, and more specifically to treatment of cleaning liquids remaining after cleaning of agricultural implements.
It is known in the agricultural arts to apply phytosanitary treatment, such as for example organic pesticides, to crops for purposes such as the reduction of pest impact and avoidance of crop diseases. The treatment chemicals are applied to a standing crop by an implement designed for such purpose.
When the implement is afterwards cleaned with washing water, the generated effluent could pollute the soil and water near the washing area. Various prior art methods have been proposed for treatment of the effluent, such as for example evaporation or filtering and storage of the dry waste product. It has been found, however, that such methods are often relatively expensive and generate waste requiring specialized handling.
It is also known in the art to employ microorganisms to biodegrade effluent, in what is sometimes called a “biological bed” or “biobed”. In one prior art method, a clay-covered pit is filled with a mixture of straw, soil and other organic material, with the microorganisms in the mixture acting to degrade the effluent upon introduction to the pit. In another biobed prior art method, described in French Patent Application No. 2896496 to Catroux et al., effluents are stored in a holding tank, pretreated to adjust acidity, and subsequently introduced into one or more biobeds for biodegradation through activation of microorganisms. However, the prior art methods may not adequately avoid environmental contamination, and in some cases where the biobed is covered by a roof the methods may suffer from inadequate evaporation of water in the effluent.
According to a first broad aspect of the present invention, there is provided a system for treating liquid effluent, the effluent comprising contaminants capable of biodegradation, the system comprising:
In some exemplary embodiments of the first aspect, the effluent comprises rinsate derived from washing agricultural implements. The contaminants may comprise phytosanitary treatment chemicals, surfactants, detergents, oils and/or organics. The containment facility may comprise containment features selected from the group consisting of a dyke inside the containment facility and a dyke outside but adjacent the containment facility.
Some embodiments of the first aspect further comprise a moisture control subsystem, the moisture control subsystem comprising:
In some embodiments, the at least one biodegradation bed is at least two biodegradation beds, the system further comprising:
The organic material in the at least one biodegradation bed preferably comprises straw. The microorganisms may comprise microorganisms naturally present in the organic material. Once treated, the treated stream preferably has reduced amounts of the contaminants compared to the effluent.
The excess amounts of the effluent are preferably directed from the at least one biodegradation bed to the sump tank by gravity, and may subsequently be directed from the sump tank to the holding tank by a sump pump situated in the sump tank.
According to a second broad aspect of the present invention, there is provided a method for treating liquid effluent, the effluent comprising contaminants capable of biodegradation, the method comprising the steps of:
In some exemplary embodiments of the second aspect, the effluent comprises rinsate derived from washing agricultural implements. The contaminants may comprise phytosanitary treatment chemicals, surfactants, detergents, oils and/or organics. The containment facility preferably comprises containment features selected from the group consisting of a dyke inside the containment facility and a dyke outside but adjacent the containment facility.
In some exemplary embodiment, the step of directing the effluent from the containment facility to at least one biodegradation bed comprises pumping the effluent. Exemplary methods may further comprise: selecting an operating moisture level for the at least one biodegradation bed; sensing a bed moisture level in the at least one biodegradation bed; comparing the bed moisture level against the operating moisture level; ceasing directing the effluent to the at least one biodegradation bed if the bed moisture level is greater than the operating moisture level; and allowing the directing of the effluent to the at least one biodegradation bed if the bed moisture level is less than the operating moisture level.
In embodiments where the at least one biodegradation bed is at least two biodegradation beds, the method preferably further comprises directing the effluent to each of the biodegradation beds. The organic material in the at least one biodegradation bed preferably comprises straw, and the microorganisms may comprise microorganisms naturally present in the organic material. The step of degrading the contaminants preferably comprises microbial biodegradation. Upon completion, the treated stream preferably has reduced amounts of the contaminants compared to the effluent.
The treated stream may directed to the sump tank by gravity, and at least a portion of the treated stream is directed from the sump tank back into the containment facility by a sump pump.
According to a third broad aspect of the present invention, there is provided a system for treating liquid effluent, the effluent comprising contaminants capable of biodegradation, the system comprising:
In some exemplary embodiments of the third aspect, the effluent comprises rinsate derived from washing agricultural implements, and the contaminants may comprise phytosanitary treatment chemicals, surfactants, detergents, oils and/or organics. Exemplary system preferably further comprise a moisture control subsystem, the moisture control subsystem comprising: at least one moisture sensor in the at least one biodegradation bed, the at least one moisture sensor configured to detect the moisture level in the at least one biodegradation bed and output a bed moisture level signal representing the bed moisture level; a moisture control station for receiving the bed moisture level signal and comparing the bed moisture level against an operating moisture level; and the moisture control station for outputting control information to the pump; such that if the bed moisture level is greater than the operating moisture level, the pump is directed by the moisture control station to cease pumping the effluent out of the holding tank; and such that if the bed moisture level is less than the operating moisture level, the moisture control station allows the pump to continue pumping the effluent out of the holding tank.
In some embodiments where the at least one biodegradation bed is at least two biodegradation beds, the system further comprises a manifold for dividing the line exit into a plurality of line exits, each of the plurality of line exits for directing the effluent to one of the biodegradation beds.
The organic material in the at least one biodegradation bed preferably comprises straw, and the microorganisms may comprise microorganisms naturally present in the organic material. Upon completion, the treated stream preferably has reduced amounts of the contaminants compared to the effluent.
In some exemplary embodiments the substantially transparent cover is composed of a clear plastic, which in some preferred embodiments may be Plexiglas™.
According to a fourth broad aspect of the present invention, there is provided a method for treating liquid effluent, the effluent comprising contaminants capable of biodegradation, the method comprising the steps of:
In some exemplary embodiments of the fourth aspect, the effluent comprises rinsate derived from washing agricultural implements, and the contaminants may comprise phytosanitary treatment chemicals, surfactants, detergents, oils and/or organics. The step of directing the effluent to the at least one biodegradation bed may comprise pumping the effluent.
Some exemplary methods further comprise: selecting an operating moisture level for the at least one biodegradation bed; sensing a bed moisture level in the at least one biodegradation bed; comparing the bed moisture level against the operating moisture level; ceasing directing the effluent to the at least one biodegradation bed if the bed moisture level is greater than the operating moisture level; and allowing the directing of the effluent to the at least one biodegradation bed if the bed moisture level is less than the operating moisture level.
Where the at least one biodegradation bed is at least two biodegradation beds, the method preferably further comprises directing the effluent to each of the biodegradation beds. The organic material in the at least one biodegradation bed preferably comprises straw, and the microorganisms may comprise microorganisms naturally present in the organic material. The step of degrading the contaminants preferably comprises microbial biodegradation, and the treated stream preferably has reduced amounts of the contaminants compared to the effluent.
A detailed description of exemplary embodiments of the present invention is given in the following. It is to be understood, however, that the invention is not to be construed as being limited to these embodiments. The exemplary embodiments are directed to a particular application of the present invention, while it will be clear to those skilled in the art that the present invention has applicability beyond the exemplary embodiments set forth herein.
In the accompanying drawings, which illustrate exemplary embodiments of the present invention:
Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings.
Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. The following description of examples of the technology is not intended to be exhaustive or to limit the invention to the precise form of any exemplary embodiment. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.
Turning to
The effluent/rinsate 24 can be extracted from the holding tank 14 by means of a tank outlet line 18, the effluent 24 drawn through the line 18 by operation of a pump 20. The pump may be of any suitable design or horsepower, which a person skilled in the art could select for a specific system and desired throughput. For one non-limiting example, the pump 20 could be an EcoPlus™ pump, 230½ hp, 1500 gph. The pump 20 operates to pump the effluent 24 through a line exit 22 adjacent the biodegradation bed 26, to introduce the effluent 24 by means of drip irrigation.
The effluent 24 is to be treated in the biodegradation bed 26, which bed 26 comprises a tank for holding a mixture 28 of soil, organic material such as straw, and microorganisms. The soil may be readily available topsoil having properties amenable to microorganism activity in the judgment of the skilled person, and microorganisms suitable for biodegradation of the contaminants may be naturally present in such soil or the organic material introduced therein. The microorganisms present in the bed contents 28 operate to degrade contaminants in the effluent 24, such as those mentioned herein, by a known process termed microbial biodegradation, in which the microorganisms are activated through the heat and moisture conditions of the bed 26 to degrade the contaminants.
However, the effectiveness of the degradation is impacted by the moisture within the bed, given that excess moisture can generate an anaerobic environment that could hinder action of the microorganisms and the desired contaminant degradation. To monitor and control moisture within the bed 26, the system 10 includes a moisture control station or panel 44, which is wired or wirelessly connected to a moisture sensor 42 positioned within the bed contents 28. The station 44 may be, for example, a Baseline 3200 Smart Controller, and the sensor may be a Baseline soil moisture senor, with a Baseline pump start relay, all manufactured by Baseline Inc. The station 44 receives signals from the sensor 42 indicating the moisture level within the bed contents 28. If the station 44 receives a signal from the sensor 42 indicating that the bed moisture is above a certain predetermined operating moisture level—which indicates that anaerobic conditions are approaching—then the station 44 sends a signal to the pump 20 to cease pumping effluent 24 out of the holding tank 14.
In a further means for controlling bed moisture and avoiding anaerobic conditions within the bed 26, the bed 26 is provided with both a bed outlet line 30 and an overflow line 32. While the bed outlet line 30 functions to allow the release of unevaporated treated effluent, it can further operate to allow the release of excess effluent that has passed downwardly through the bed contents 28. In addition, if an undesired high volume of effluent passes into the bed 26, some of that excess may exit the bed 26 by means of the overflow line 32. Both the bed outlet line 30 and the overflow line 32 connect to a sump feed line 46, and pass into a sump tank 34, thus draining the bed 26 of undesired moisture.
The sump tank 34 is positioned outside the containment facility 16, and it contains a sump pump 36. The sump pump 36 may be, for example, a Bur Can ½ hp submersible 1500 gph pump. In the illustrated embodiment, once the sump tank 34 is filled to a certain predetermined level, the sump pump 36 initiates operation and pumps the received fluid through the sump outlet line 38 and into the tank inlet line 12, thus allowing the fluid to be reintroduced into the holding tank 14 for further processing when the bed 26 is dry enough for further effluent 24 introduction.
As can be seen in
Turning to
Each of the sensors 42a,b sends a signal to the station 44, indicating the moisture level in their respective beds 26a,b. The station 44 compares each moisture level against the predetermined operating moisture level and determines if additional effluent 24 introduction should be halted. If the station 44 determines that the moisture level is too high, the station 44 sends a signal to the manifold 52 instructing it to close off supply to one or both (as the case may be) of the line exits 22a,b. In this way, the pump 20 may remain operative but supply to the beds 26a,b may be managed independently.
Turning now to
If the bed moisture is lower than the predetermined operating moisture level, effluent is pumped to the bed at step 70 for degradation. At step 72 of the method 60, the effluent is allowed to pass downwardly through the bed contents, such that the contaminants are placed into contact with the microorganisms that will degrade them through a process of microbial biodegradation. The treated stream, which is at least partially decontaminated, and any excess effluent that has been allowed to bypass the treatment (as described above), is directed to a sump tank for holding at step 74. At least a portion of this stream is subsequently directed to the containment facility at step 76.
Turning now to
The moisture of the degradation bed is sensed at step 86, as degradation would be negatively impacted by an anaerobic reaction environment. At step 88 an assessment is made as to whether the bed moisture is greater than the predetermined operating moisture level, and if the bed moisture is greater then monitoring continues at step 86.
If the bed moisture is lower than the predetermined operating moisture level, effluent is pumped to the bed at step 90 for degradation. At step 92 the effluent is allowed to pass downwardly through the bed contents, such that the contaminants are placed into contact with the microorganisms that will degrade them through a process of microbial biodegradation. At step 94, given the presence of a transparent cover, sunlight is allowed to pass through the cover and heat the bed contents and the effluent.
Unless the context clearly requires otherwise, throughout the description and the claims:
Words that indicate directions such as “vertical”, “transverse”, “horizontal”, “upward”, “downward”, “forward”, “backward”, “inward”, “outward”, “vertical”, “transverse”, “left”, “right”, “front”, “back”, “top”, “bottom”, “below”, “above”, “under”, and the like, used in this description and any accompanying claims (where present) depend on the specific orientation of the apparatus described and illustrated. The subject matter described herein may assume various alternative orientations. Accordingly, these directional terms are not strictly defined and should not be interpreted narrowly.
Where a component (e.g. a circuit, module, assembly, device, drill string component, drill rig system etc.) is referred to herein, unless otherwise indicated, reference to that component (including a reference to a “means”) should be interpreted as including as equivalents of that component any component which performs the function of the described component (i.e., that is functionally equivalent), including components which are not structurally equivalent to the disclosed structure which performs the function in the illustrated exemplary embodiments of the invention.
Specific examples of methods and apparatus have been described herein for purposes of illustration. These are only examples. The technology provided herein can be applied to contexts other than the exemplary contexts described above. Many alterations, modifications, additions, omissions and permutations are possible within the practice of this invention. This invention includes variations on described embodiments that would be apparent to the skilled person, including variations obtained by: replacing features, elements and/or acts with equivalent features, elements and/or acts; mixing and matching of features, elements and/or acts from different embodiments; combining features, elements and/or acts from embodiments as described herein with features, elements and/or acts of other technology; and/or omitting combining features, elements and/or acts from described embodiments.
The foregoing is considered as illustrative only of the principles of the invention. The scope of the claims should not be limited by the exemplary embodiments set forth in the foregoing, but should be given the broadest interpretation consistent with the specification as a whole.
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